Restoring a buffet for birds on North Breton Island
Any mention of Louisiana frequently d conjures up images of delicious Cajun and Creole food – po’boys, gumbo, jambalaya and more. “Barrier islands” probably won’t pop into most people’s heads. But these islands are vitally important because they protect Louisiana communities from the impact of storms by acting like speed bumps, absorbing wind and wave energy. In addition, they provide essential habitat for birds and other wildlife.
North Breton Island, part of the Breton National Wildlife Refuge, is one such barrier island. For thousands of years, though, this speed bump, located a 45-minute boat ride from Venice, Louisiana, has slowly eroded away due to natural conditions such as severe storms. The island’s lost shoreline has translated into lost habitat for numerous federally protected birds.
North Breton Island has suffered from man-made disasters as well. Like many other barrier islands in the Gulf of Mexico, it was hit hard by the 2010 Deepwater Horizon oil spill. Fortunately, that disaster led to a positive outcome: funding for the island’s restoration is being paid for by BP, the company responsible for the spill.
After the oil spill, federal and state agencies came together to form the Deepwater Horizon Natural Resource Damage Assessment Trustee Council. The Council studied the effects of the oil spill and is now restoring the Gulf of Mexico to the condition it would have been in if the spill had not happened. The Council is using $72 million from the historic settlement with BP to increase North Breton Island by hundreds of acres.
The project will pump sand from a local underwater source, called a borrow site, and use it to expand the size of the island, which is now only a tiny fraction of the size it was hundreds of years ago. The additional acreage will provide nesting habitats for threatened and endangered birds such as the brown pelican and least tern. It will also benefit the red knots and piping plovers that forage for food there in the winter.
“We don’t expect the project will impact the red knot and plovers, but it will impact their food source,” says Robin Donohue, a biologist from the U.S. Fish and Wildlife Service. He recently joined other Service and U.S Geological Survey (USGS) biologists in establishing the benchmarks for the number and types of worms, crustaceans and other invertebrates that call North Breton Island’s shoreline home before the expansion.“These small animals are incredibly important in that they’re the bottom of that beach-foraging food chain,” Donohue said. “For virtually all of your shorebirds — that’s what they’re looking for.”
So Donohue and his colleagues went looking for invertebrates on North Breton Island, too. Using a soil sampling tube, they took samples of the shoreline down to 5 centimeters deep.
“We had to do it as fast as possible to get the invertebrates before they run away,” he said with a laugh. “Shorebirds looking for lunch are much stealthier and quieter than a bunch of biologists.”
A USGS expert is examining the samples to determine the shoreline’s invertebrate population now, before construction starts in 2019. After approximately 8.2 million cubic yards of sand, silt, and clay dredged from a nearby borrow site is put into place and the North Breton Island shoreline is reconfigured, biologists will take samples again in order to compare the post-construction invertebrate population with the pre-project baseline.
With those hungry shorebirds and other species in mind, the biologists are aiming to have at least 70 percent of the pre-project invertebrate biomass re-established within two years of the project’s completion. That would be a normal rate of return, and they’ll be looking for it to ensure the restoration effort is on track.
“Through our sampling, we will have an idea of the beach critter community,” said Chris Pease, another Service biologist who was involved. “And after we add new sand to the island as part of our restoration efforts,” he says, “we will know if the birds will have as good of a buffet as before.”
Nadine Siak, Public Affairs Specialist